A series of parking aids are known for supporting the drivers of motor vehicles during parking. In the simplest case, these are proximity/distance sensors that warn against collision with other vehicles, curbs and other obstacles.
More complex systems determine here the size of a parking space which has already been detected as a possibility by the driver and perform the actual parking procedure by means of fully automatic transverse and longitudinal guidance.
Patent document WO 97/47991 A1 thus describes a method for determining and dimensioning free spaces between vehicles parked at the edge of the road. Here, the intermediate space is sensed as the measuring device drives by using a distance-resolving sensor.
Patent document DE 198 09 416 A1 discloses a system for supported parking in which objects in the proximity around the motor vehicle and their distances from the motor vehicle are sensed by an all-round sensor system with a multiplicity of distance sensors. After a potential parking space has been driven to, it is sensed by means of sensors arranged on the motor vehicle. A processing device which is connected downstream of the sensors determines the size of the potential parking space from the sensed distance data and, if appropriate, calculates a possible strategy for parking.
A disadvantage with the known systems is the fact that basically the traffic space to the side of the vehicle is measured, so that the size of the parking space cannot be determined until the vehicle to be parked is already located directly next to it or has even already passed it. Owing to the high traffic density it is therefore often virtually impossible in real road traffic for the vehicle to brake and initiate the parking procedure, or even reverse to the detected parking space, in good time without constituting a traffic hazard.